ORA-12801: error signaled in parrallel query server …
The ORA-12801 is error signaled in parrallel query server error is thrown by the query coordinator (QC) as reaction of an underlying problem (i. e. it does not describe the actual issue).
create table tq84_ora_12801 (n varchar2(50));
insert into tq84_ora_12801 select level from dual connect by level <= 1e6;
-- This is not a zero but the uppercase letter O!
insert into tq84_ora_12801 values ('O');
commit;
select /*+ parallel */ max(to_number(n)) from tq84_ora_12801;
-- ORA-12801: error signaled in parallel query server P005
-- ORA-01722: invalid number
In order to suppress the ora-12801 in the error stack and go directly to the underlying error message, use event 10397.